1. Field of the Invention
The present invention relates to an infrared clinical thermometer which detects infrared rays radiated from an ear drum.
2. Description of the Background Art
A conventional infrared clinical thermometer which detects infrared rays radiated from an ear drum is known.
In such an infrared clinical thermometer, a measurement switch is depressed while a probe is inserted into an external ear canal, the intensity of infrared rays radiated from an ear drum is detected by the probe, and a body temperature (more specifically, ear drum temperature) is measured on the basis of the detection result.
Measuring procedures performed when measurement is performed by using an infrared clinical thermometer according to a conventional art will be briefly described below. FIG. 9 is a flow chart which shows measuring procedures of the infrared clinical thermometer according to the conventional art.
A power supply is turned on (S60), and a probe is inserted into an ear (external ear canal) (S61). In this state, when a measurement switch (SW) is depressed (S62), an infrared sensor arranged inside the probe receives infrared rays from an ear drum to measure an intensity of infrared rays (measurement operation by an A/D converter or the like) (S63). A body temperature is calculated on the basis of the measurement result (S64), and the body temperature is displayed on an LCD or the like (S65).
The following art is known (trade name: OMRON MC-505) is known. That is, measurement (A/D conversion) is performed a plurality of times in (S63), and a mean of the plurality of A/D-converted values is used (S64), so that a more accurate body temperature can be measured.
As described above, in the conventional art, the measurement switch is depressed while the probe is inserted into an external ear canal to measure a body temperature. However, in this case, the measurement may be performed while a condition where the probe is inserted is not clear, and a measurement error may be increased.
More specifically, when the light-receiving surface of an infrared sensor arranged inside the probe does not accurately face the ear drum, the intensity of infrared rays radiated from the ear drum cannot be accurately measured. When the probe is inclined, the temperature of the external ear canal is measured.
FIG. 10 is a diagram which shows measurement results of temperature distributions of an ear drum 70 and an external ear canal 71. As shown in FIG. 10, it is understood that the temperature of the ear drum 70 is the highest inside the ear, and the temperature gradually decreases as it is away from the ear drum. In FIG. 10, the mean and dispersion of measurement results of a plurality of persons are shown.
In order to cancel the above drawbacks, in, e.g., Japanese Unexamined Patent Publication No. 8-215154 and U.S. Pat. No. 5,325,863, an art which employs a peak hold method which determines a body temperature by using the highest value of a plurality of measured values is disclosed.
According to this art, since a body temperature is calculated by a peak value of measured temperatures, possibility that a temperature obtained when a probe accurately faces an ear drum is captured is high.
However, in the conventional art described above, the following problems are posed.
First, the peak hold method described above is used, possibility that a body temperature obtained when an insertion condition of a probe is proper can be measured is high. However, a user cannot understand an insertion condition of the probe. For this reason, the body temperature may be measured while the insertion condition of the probe is still improper.
Therefore, in order to cause a user to learn a correct insertion position, the user must measure a plurality of times to be accustomed to use an infrared clinical thermometer.
Secondly, when measurement is performed while a probe is inserted into an external ear canal for a long time, or when measurement is repeated many times, a measurement error is large when measurement is performed while the temperature inside the probe is increased by heat received from the external ear canal or the like.
In the infrared clinical thermometer according to the conventional art, an interval for making it possible to perform the next measurement upon completion of the measurement may be set. However, since this interval is a fixed period of time, an interval until accurate measurement can be performed cannot be taken, and a measurement error may increase.
The interval time is started upon completion of the measurement regardless of the conditions or the like of the probe. For this reason, upon completion of the measurement, even though the probe is still inserted in the external ear canal, measurement can be performed after a fixed period of time. Therefore, the measurement error increases as described above.
Third, when the peak hold method is employed, a measurement error is generated depending on the surrounding environment temperature.
More specifically, in the peak hold method, a temperature is measured even though the probe does not face the ear drum, and the temperature is stored (held). For this reason, when the surrounding environment temperature is higher than the body temperature, before the probe is inserted into the external ear canal, the environment temperature has been stored. The surrounding temperature which is higher than the body temperature is measured.
The present invention has been made to solve the problems of the prior art, and has as its object to provide a reliable infrared clinical thermometer which can more accurately measure a temperature of an ear drum itself.
In order to achieve the above object, according to the present invention, there is provided an infrared clinical thermometer which has a probe inserted into an external ear canal, and a detection sensor, arranged inside the probe, for detecting infrared rays radiated from an ear drum, including: detection means for detecting an insertion condition of the probe into the external ear canal; and permission means for permitting measurement depending on a detection result obtained by the detection means.
The permission of measurement by the permission means that measurement can be performed. Therefore, when measurement by the permission means is not permitted, for example, even though a measurement switch is depressed while the probe is inserted into the external ear canal, measurement is not performed.
According to the configuration of the present invention, measurement is performed only when an insertion condition of the probe into the external ear canal is proper, a measurement error caused by an improper insertion condition can be prevented.
The infrared clinical thermometer preferably includes notification means for notifying a user of measurement permission by the permission means.
As the notification means, for example, means realized by a buzzer, a voice message, or the like can be used.
According to this configuration, it can be known that the insertion condition of the probe into the external ear canal is proper.
The detection means preferably detects the insertion condition of the probe into the external ear canal on the basis of a detection result continuously detected by the detection sensor.
The detection means preferably includes decision means for deciding whether the probe is inserted into the external ear canal or not depending on whether an infrared intensity or a temperature calculated from the infrared intensity falls within a predetermined range or not on the basis of the detection result continuously detected by the detection sensor.
The xe2x80x9cinfrared intensity or the temperature calculated from the infrared intensityxe2x80x9d means that the decision may be directly performed by the infrared intensity or may be performed by the temperature calculated from the infrared intensity. More specifically, in order to decide whether the probe is inserted into the external ear canal, the decision is performed by the detected temperature itself. However, in general, the temperature is obtained by converting the infrared intensity serving as analog data into digital data. Since a result obtained by performing the decision before the conversion is the same as a result obtained by performing the decision after the conversion, the decision may be performed by the infrared intensity or the temperature calculated by the infrared intensity.
The decision means preferably fixes the decision that the probe is inserted into the external ear canal when the infrared intensity or the temperature calculated by the infrared intensity is held within the predetermined range for a predetermined time after the infrared intensity or the temperature calculated by the infrared intensity changes from an outside of the predetermined range to the predetermined range.
According to this configuration, the decision can be prevented from being performed when the insertion condition is unstable. Decision mistakes can be reduced.
The decision means preferably fixes the decision that the probe is removed from the external ear canal when the infrared intensity or the temperature calculated by the infrared intensity is held within the predetermined range for a predetermined time after the infrared intensity or the temperature calculated by the infrared intensity changes from the predetermined range to the outside of the predetermined range.
According to this configuration, the decision can be prevented from being performed when the insertion condition is unstable. Decision mistakes can be reduced.
The infrared clinical thermometer preferably includes storage means for storing data continuously detected by the detection sensor after the decision that the probe is inserted into the external ear canal is performed by the decision means, and at least one of the data stored in the storage means is preferably handled as data used in body temperature measurement.
According to this configuration, the probe can measure a body temperature in a condition where the probe is inserted into the external ear canal.
The infrared clinical thermometer preferably includes a switch for stopping a storing operation by the storage means.
The infrared clinical thermometer preferably includes time measurement means for measuring an elapsed time after the decision that the probe is inserted into the external ear canal is performed by the decision means, and the storing operation by the storage means is preferably stopped after it is measured by the time measurement means that a predetermined time has elapsed.
According to this configuration, a measurement error caused by the inside of the probe is heated by heat received from the external ear canal when the probe is inserted in the external ear canal for a long time can be reduced.
The infrared clinical thermometer preferably includes warning means for giving warning to a user when it is measured by the time measurement means that a predetermined time has elapsed before the storing operation is stopped by the switch.
According to this configuration, the user can know that the measurement is not performed.
Data corresponding to data in which the infrared intensity or the body temperature calculated by the infrared intensity is maximum of data stored in the storage means is preferably handled as data used in body temperature measurement.
According to this configuration, when the infrared intensity or the body temperature calculated by the infrared intensity is maximum, the probability that the infrared sensor correctly faces the ear drum is high, and the temperature of the ear drum can be more reliably measured.
The storage means preferably sequentially updates data to be stored such that only the data corresponding to the data in which the infrared intensity or the body temperature calculated by the infrared intensity is maximum from the data continuously detected by the detection sensor.
The infrared clinical thermometer preferably includes: a first mode in which data used in measurement is selected from data detected by the detection sensor depending on a detection result obtained by the detection means; and a second mode in which detection data obtained by the detection sensor immediately after detection instruction is performed is used by measurement regardless of the detection result obtained by the detection means.
According to this configuration, the detection means itself does not properly functions first of all due to a surrounding environment temperature or the like, only the data detected by the detection sensor immediately after the detection instruction is performed can be used by performing measurement in the second mode, and, when the temperatures which have been measured up to this include an environment temperature, the data can be prevented from being handled as measurement data.
The infrared clinical thermometer preferably includes: temperature detection means for detecting a temperature inside the probe; and mode switching means for switching the present mode to the second mode when it is detected by the temperature detection means that the temperature is not less than a predetermined temperature.
According to this configuration, for example, the predetermined temperature above is set to be a temperature closed to a temperature of general human beings"" body temperature. In this case, when the environment temperature is not less than the temperature, the present mode is automatically switched to the second mode, so that the environment temperature can be prevented from being handled as measurement data.
The infrared clinical thermometer preferably includes estimation means for estimating a convergence temperature from a change in temperature detected by the temperature detection means, and the mode switching means preferably switches the present mode to the second mode when the temperature estimated by the estimation means is not less than a predetermined temperature.
According to this configuration, even though measurement is performed immediately after a position where measurement is performed is changed from a position where an environment temperature is low to a position where an environment temperature is high, the present mode is automatically switched to the second mode, so that the environment temperature can be prevented from being handled as measurement data.
A temperature condition used in a decision of switching obtained when the present mode is switched to the second mode by the mode switching means on the basis of the temperature detected by the temperature detection means is preferably different from a temperature condition used in a decision of switching obtained when the present mode is switched to the second mode on the basis of the temperature estimated by the estimation means.
According to this configuration, for example, an estimation error generated by the estimation means can be canceled.
According to the present invention, an infrared clinical thermometer which has a probe inserted into an external ear canal, and a detection sensor for detecting infrared rays radiated from an ear drum, includes: inhibition means for inhibiting measurement of a body temperature in a predetermined period after the body temperature is measured; and setting means for setting the predetermined period every measurement.
According to the configuration of the present invention, measurement of a body temperature is inhibited by the inhibition means in the predetermined period, so that a measurement error generated by a high temperature inside the probe caused by performing measurement can be canceled. Since the predetermined period can be set by the setting means every measurement, a proper process can be performed depending on a using state or the like.
The setting means preferably sets the predetermined time on the basis of a time required for measurement.
According to this configuration, since the internal temperature generally increases as the time required for measurement becomes long, a time for inhibiting measurement is preferably set to be long to cancel the measurement error. When the predetermined time is set on the basis of the time required for measurement, a measurement error based on an increase in internal temperature caused by measurement can be reduced. Waste of time caused when an inhibition time is needlessly lengthened can be reduced.
The infrared clinical thermometer preferably includes: temperature detection means for detecting a temperature inside the probe, and the setting means preferably sets the predetermined time on the basis of the detection result of the temperature detection means.
Therefore, a measurement error based on an excessively high internal temperature can be reduced.